1. Field of the Invention
The present invention generally relates to an OMA (Open Mobile Alliance) XDM (eXtensible Markup Language (XML) Document Management) service enabler, and more particularly to an XDM system and a method using the position description of an XML document.
2. Description of the Related Art
As generally known in the art, an XDM v1.0 service enabler implements an XDM operation for creating an XML document in an XDMS (XDM Server) by transmitting an XML document, which is to be created, to the XDMS while being contained in an XCAP (XML Configuration Access Protocol) PUT request message.
The flow of messages during an XDM operation for creating an XML document of URI (Uniform Resource Identifier) list in a shared XDMS will now be described with reference to FIG. 1, and Tables 1 and 2 given below.
An XDMC (XDM Client) transmits an XCAP PUT request message, which contains an XML document to be created, to the XDMS in step 10 of FIG. 1. When the XCAP PUT request message is composed as shown in Table 1, the XDMC may use the XCAP PUT request message to request that the friends.xml document, which contains a URI list included in the content body, be created in the user directory of sip:jay@example.com.
TABLE 1PUT http://xcap.example.com/resource-lists/users/sip:jay@example.com/friends.xml HTTP/1.1 Host: xcap.example.com User-Agent: XDM-client/OMA1.0 Date: Thu, 25 July 2006 18:59:57 GMT+9 X-XCAP-Asserted -Identity: “sip:jay@example.com ” Content-Type: application/resource-lists+xml Content-Length: (_)  <?xml version=“1.0” encoding=“UTF-8”?> <resource-lists xmlns=“urn:ietf:params:xml:ns:resource-lists”>  <list name=“My_friends”>   <entry uri=“sip:friend1@example.com”>    <display-name>Friend1</display-name>   </entry>  </list> </resource-lists> 
Upon receiving the XCAP PUT request message shown in Table 1, the XDMS creates a corresponding XML document and transmits an XCAP 201 Created message 12 of FIG. 1 to the XDMC to inform of successful creation. The XCAP 201 Created message 12 of FIG. 1 is composed as shown in Table 2 below.
TABLE 2HTTP/1.1 201 CREATED Server: XDM-serv/OMA1.0 Date: Thu, 25 July 2006 19:00:00 GMT+9 Etag: “eti87” Content-Length: 0 
As mentioned above, an XML document can be created in the XDMS using the XDM of XDM v1.0 service enabler. Furthermore, an XDM v2.0 service enabler supports new XDM functions, including XDM Copying and XDM Forwarding. These functions are used to retrieve an XML document already existing in the XDMS or deliver the XML document to another user [XDM2_RD] (Reference: “OMA XML Document Management Requirements,” Version 2.0, Open Mobile Alliance, OMA-RD-XDM-V2—0, URL:http://www.openmobilealliance.org/). Therefore, when these are implemented by using an existing XDM function for creating an XML document in the XDMS, the XDMC transmits an XCAP GET request to retrieve a corresponding XML document from the XDMS in steps 20 and 22 of FIG. 2. Then, the XDMC adds the XML document, which has been retrieved from the XDMS, to an XCAP PUT request so the document is created and stored in a desired XDMS in steps 24 and 26 of FIG. 2.
The fundamental reason for the above-mentioned process is that, in order to create a new XML document in the XDMS, the corresponding XML document needs to be included in the XCAP PUT request, as has been described with regard to the creation of an XML document in the XDMS by the XDM v1.0 service enabler.
In other words, the XDMC retrieves an XML document, which is already stored in the XDMS, and stores the XML document again in the XDMS. This results in the redundant information being exchanged, and thus causing signaling overhead. Further, considering that the XDM service enabler provides services in wireless environments and thus that the above-mentioned signaling occurs over a wireless channel, such signaling overhead would result in resource waste and processing time delay.